1. (Field of the Invention)
The present invention relates to a recording apparatus having a flash fusing apparatus and more particularly to a recording apparatus having a flash fusing apparatus wherein the toner is heated and fused on the recording paper by means of the flashlight. The flash fusing apparatus is applied for use in the recording apparatus such as the laser beam printers and the facsimile equipment etc. wherein the image is recorded on the recording paper by the toner. The fusing toner image can be obtained efficiently utilizing cut sheets having a predetermined length for the recording paper through the flash fusing apparatus.
2. (Description of the Prior Art)
A conventional flash fusing apparatus is applied for use in the recording apparatus such as the laser beam printers and the facsimile equipment etc.. In such a flash fusing apparatus in the recording apparatus, the toner is attached on the recording paper by the electrostatic energy for development process, and in fusing process the toner is heated and fused on the recording paper by photoflash of the xenon flash lamp etc. so as to form the image on the recording paper by the toner.
It is desirable to supply efficiently the fusing energy on the fusing portion of the flash fusing apparatus when the cut sheet is used as the recording paper in the recording apparatus, the gap is found inevitably between a precede recording paper and a next recording paper. Namely, no recording paper area portion exists as the gap on the recording paper carrying apparatus.
When the cut sheet is used as the recording paper and the flashlight by the xenon flash lamp irradiates with synchronously the carrying velocity of the recording paper as same as the printing with the continuous recording paper, the fusing energy by the flash fusing apparatus is supplied on the gap, then the recording paper carrying apparatus of the recording apparatus is heated. Thereby, the recording paper may be deformed, in the worse case the danger of ignition accompany also. Further there are various inconvenient problems such as waste of electric power so as to supply to unnecessary fusing energy on the gap.
A conventional recording apparatus is disclosed in, for example Japanese Utility Model Laid-Open No. 86429/1977, in which it is possible to print utilizing a cut sheet as a recording paper. In such a recording apparatus, a detector for detecting the recording paper is disposed at a recording paper carrying apparatus which is positioned at just under the fusing portion of the flash fusing apparatus. The recording paper detector comprises a photodiode and detects the fact that the recording paper reaches at just under the fusing portion of the flash fusing apparatus.
According to the detection signal by the recording paper detector, the flashlight starts by the xenon flash lamp, and then the fusing energy is supplied when the recording paper is positioned at just under the fusing portion of the flash fusing apparatus.
In the conventional recording apparatus, because that the light intensity of the flashlight of the xenon flash lamp is strong extremely, even if the recording paper exists between the recording paper detector and the xenon flash lamp, the recording paper detector may make an error in the motion. Therefore, the life time of the recording paper detector is shortened, the recording paper detector may easy to break.
For prevent the above mentioned inconvenience of the recording apparatus shown in Japanese Utility Model Laid-Open No. 86429/1977, a shutter mechanism is provided so as to cover the recording paper detector during the flashlight irradiation of the xenon flash lamp. However, when the shutter mechanism is used in the recording apparatus, it requires the shutter mechanism having high light shielding function because that the light intensity of the flashlight is strong.